Re: [PATCH v2 2/2] drm/amdgpu: move VM PTE MTYPE override to per-PTE granularity

["Christian König" <christian.koenig@amd.com>]

On 4/20/26 15:37, Philip Yang wrote:
> Refactor the NUMA-aware MTYPE override for VM page table entries:
> 
> - Move the override_vm_pte_flags call from the centralized
>   amdgpu_vm_pte_update_flags() into the individual CPU and SDMA update
>   backends, enabling per-PTE MTYPE override including for scattered
>   pages (pages_addr path).
> 
> - Move APU, IP version, and direct-mapped eligibility checks from
>   runtime (gmc_v9_0_override_vm_pte_flags) to init time
>   (gmc_v9_0_set_gmc_funcs), selecting between gmc_funcs structs with
>   and without the override function pointer to avoid repeated runtime
>   checks on every PTE update.
> 
> - Guard allow_override on whether gmc_funcs->override_vm_pte_flags is
>   actually implemented.
> 
> Signed-off-by: Philip Yang <Philip.Yang@amd.com>

Reviewed-by: Christian König <christian.koenig@amd.com>

> ---
>  drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h     |  2 ++
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c      |  2 +-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h      |  6 ++--
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c  | 11 ++++++-
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c   |  9 ------
>  drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 11 ++++++-
>  drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c       | 35 +++++++++------------
>  7 files changed, 41 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> index 6ab4c1e297fc..c6d7a9e54eb3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gmc.h
> @@ -365,6 +365,8 @@ struct amdgpu_gmc {
>  	bool flush_tlb_needs_extra_type_0;
>  	bool flush_tlb_needs_extra_type_2;
>  	bool flush_pasid_uses_kiq;
> +
> +	bool override_pte;
>  };
>  
>  #define amdgpu_gmc_emit_flush_gpu_tlb(r, vmid, addr) (r)->adev->gmc.gmc_funcs->emit_flush_gpu_tlb((r), (vmid), (addr))
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> index 63156289ae7f..532b78701bbe 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
> @@ -1163,7 +1163,7 @@ int amdgpu_vm_update_range(struct amdgpu_device *adev, struct amdgpu_vm *vm,
>  	params.pages_addr = pages_addr;
>  	params.unlocked = unlocked;
>  	params.needs_flush = flush_tlb;
> -	params.allow_override = allow_override;
> +	params.override_pte = allow_override && adev->gmc.override_pte;
>  	INIT_LIST_HEAD(&params.tlb_flush_waitlist);
>  
>  	amdgpu_vm_eviction_lock(vm);
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> index f33ea7f8509b..a0435468d0bd 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.h
> @@ -296,10 +296,10 @@ struct amdgpu_vm_update_params {
>  	bool needs_flush;
>  
>  	/**
> -	 * @allow_override: true for memory that is not uncached: allows MTYPE
> -	 * to be overridden for NUMA local memory.
> +	 * @override_pte: true for memory that is not uncached and gmc override function is
> +	 * implemented to allow MTYPE to be overridden for NUMA local memory.
>  	 */
> -	bool allow_override;
> +	bool override_pte;
>  
>  	/**
>  	 * @tlb_flush_waitlist: temporary storage for BOs until tlb_flush
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
> index f078db3fef79..b31ff6f56f0d 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_cpu.c
> @@ -88,12 +88,21 @@ static int amdgpu_vm_cpu_update(struct amdgpu_vm_update_params *p,
>  
>  	trace_amdgpu_vm_set_ptes(pe, addr, count, incr, flags, p->immediate);
>  
> +	if (!p->pages_addr && p->override_pte)
> +		amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, addr, &flags);
> +
>  	for (i = 0; i < count; i++) {
> +		u64 oflags = flags;
> +
>  		value = p->pages_addr ?
>  			amdgpu_vm_map_gart(p->pages_addr, addr) :
>  			addr;
> +
> +		if (p->pages_addr && p->override_pte)
> +			amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, value, &oflags);
> +
>  		amdgpu_gmc_set_pte_pde(p->adev, (void *)(uintptr_t)pe,
> -				       i, value, flags);
> +				       i, value, oflags);
>  		addr += incr;
>  	}
>  	return 0;
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
> index 31a437ce9570..883cc275f354 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_pt.c
> @@ -707,15 +707,6 @@ static void amdgpu_vm_pte_update_flags(struct amdgpu_vm_update_params *params,
>  	if (level == AMDGPU_VM_PTB)
>  		amdgpu_vm_pte_update_noretry_flags(adev, &flags);
>  
> -	/* APUs mapping system memory may need different MTYPEs on different
> -	 * NUMA nodes. Only do this for contiguous ranges that can be assumed
> -	 * to be on the same NUMA node.
> -	 */
> -	if ((flags & AMDGPU_PTE_SYSTEM) && (adev->flags & AMD_IS_APU) &&
> -	    adev->gmc.gmc_funcs->override_vm_pte_flags &&
> -	    num_possible_nodes() > 1 && !params->pages_addr && params->allow_override)
> -		amdgpu_gmc_override_vm_pte_flags(adev, params->vm, addr, &flags);
> -
>  	params->vm->update_funcs->update(params, pt, pe, addr, count, incr,
>  					 flags);
>  }
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
> index 36805dcfa159..2eb64df6daa9 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c
> @@ -257,6 +257,9 @@ static int amdgpu_vm_sdma_update(struct amdgpu_vm_update_params *p,
>  		}
>  
>  		if (!p->pages_addr) {
> +			if (p->override_pte)
> +				amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, addr, &flags);
> +
>  			/* set page commands needed */
>  			amdgpu_vm_sdma_set_ptes(p, bo, pe, addr, count,
>  						incr, flags);
> @@ -275,8 +278,14 @@ static int amdgpu_vm_sdma_update(struct amdgpu_vm_update_params *p,
>  		p->num_dw_left -= nptes * 2;
>  		pte = (uint64_t *)&(p->job->ibs->ptr[p->num_dw_left]);
>  		for (i = 0; i < nptes; ++i, addr += incr) {
> +			u64 oflags = flags;
> +
>  			pte[i] = amdgpu_vm_map_gart(p->pages_addr, addr);
> -			pte[i] |= flags;
> +
> +			if (p->override_pte)
> +				amdgpu_gmc_override_vm_pte_flags(p->adev, p->vm, pte[i], &oflags);
> +
> +			pte[i] |= oflags;
>  		}
>  
>  		amdgpu_vm_sdma_copy_ptes(p, bo, pe, nptes);
> diff --git a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> index e7b78027002b..aca7841173f3 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gmc_v9_0.c
> @@ -1204,21 +1204,6 @@ static void gmc_v9_0_override_vm_pte_flags(struct amdgpu_device *adev,
>  {
>  	int local_node, nid;
>  
> -	/* Only GFX 9.4.3 APUs associate GPUs with NUMA nodes. Local system
> -	 * memory can use more efficient MTYPEs.
> -	 */
> -	if (!(adev->flags & AMD_IS_APU) ||
> -	    amdgpu_ip_version(adev, GC_HWIP, 0) != IP_VERSION(9, 4, 3))
> -		return;
> -
> -	/* Only direct-mapped memory allows us to determine the NUMA node from
> -	 * the DMA address.
> -	 */
> -	if (!adev->ram_is_direct_mapped) {
> -		dev_dbg_ratelimited(adev->dev, "RAM is not direct mapped\n");
> -		return;
> -	}
> -
>  	/* MTYPE_NC is the same default and can be overridden.
>  	 * MTYPE_UC will be present if the memory is extended-coherent
>  	 * and can also be overridden.
> @@ -1231,11 +1216,7 @@ static void gmc_v9_0_override_vm_pte_flags(struct amdgpu_device *adev,
>  		return;
>  	}
>  
> -	/* FIXME: Only supported on native mode for now. For carve-out, the
> -	 * NUMA affinity of the GPU/VM needs to come from the PCI info because
> -	 * memory partitions are not associated with different NUMA nodes.
> -	 */
> -	if (adev->gmc.is_app_apu && vm->mem_id >= 0) {
> +	if (vm->mem_id >= 0) {
>  		local_node = adev->gmc.mem_partitions[vm->mem_id].numa.node;
>  	} else {
>  		dev_dbg_ratelimited(adev->dev, "Only native mode APU is supported.\n");
> @@ -1344,6 +1325,20 @@ static const struct amdgpu_gmc_funcs gmc_v9_0_gmc_funcs = {
>  static void gmc_v9_0_set_gmc_funcs(struct amdgpu_device *adev)
>  {
>  	adev->gmc.gmc_funcs = &gmc_v9_0_gmc_funcs;
> +
> +	/* Only GFX 9.4.3 APUs associate GPUs with NUMA nodes, local system
> +	 * memory can use more efficient MTYPEs.
> +	 *
> +	 * APUs mapping system memory may need different MTYPEs on different
> +	 * NUMA nodes.
> +	 *
> +	 * Only direct-mapped memory allows us to determine the NUMA node from
> +	 * the DMA address.
> +	 */
> +	adev->gmc.override_pte = adev->gmc.is_app_apu &&
> +				 num_possible_nodes() > 1 &&
> +				 amdgpu_ip_version(adev, GC_HWIP, 0) == IP_VERSION(9, 4, 3) &&
> +				 adev->ram_is_direct_mapped;
>  }
>  
>  static void gmc_v9_0_set_umc_funcs(struct amdgpu_device *adev)